Thermal spraying refers to coating or material-addition processes wherein materials are sprayed onto a surface or substrate. The materials that form the coating are typically heated by electrical or chemical means. Thermal spraying has many desirable properties, including the ability to apply thick coatings, for example metal coatings, over large areas and with relatively high speed. Materials used in thermal spraying include metals, alloys, ceramics, plastics, and composites. Thermal spraying modalities include plasma spraying, detonation spraying, wire arc spraying, flame spraying, and high velocity oxy-fuel coating spraying.
Wire arc spray, also called twin-wire arc spray, is a thermal spraying technique using two consumable metal wires that are more-or-less continuously fed in spaced-apart relation into a spray head, sometimes referred to as a spray gun. The two wires are electrified, for example, with a welding machine, and the distal ends of the two wires are angled toward each other. An electric arc generated between the ends of the wires causes the wires to melt in the region of the arc. One or more air jets are directed toward the arc region to entrain the molten feedstock, and transports it to the desired substrate.
In U.S. Pat. Nos. 4,512,513 and 4,624,410, to Rogers (which are hereby incorporated by reference in their entirety), one of the present inventors discloses an arc metal spray apparatus and method for wire arc spray that includes monitoring the distal ends of the wires and temporarily stopping the wire feed process if a failure occurs, such that the system clears the failure by allowing the ends of the wires to melt and become vaporized. Rogers also discloses a wire arc spray system wherein multiple spray heads are mounted to a carriage system with the nozzles directed downward, such that the multiple spray heads can be moved along a path transversely and longitudinally to apply a coating to a substrate.
In U.S. Pat. No. 5,791,560, to Rogers et al. (which is hereby incorporated by reference in its entirety), one or more of the present inventors discloses a wire arc spray head, system, and method wherein a plurality of pressurized gas streams are directed toward the electrical arc to atomize, cool, and uniformly distribute the molten metal into a desired spray pattern.
In U.S. Pat. No. 6,190,740, to Rogers (which is hereby incorporated by reference in its entirety), one of the present inventors discloses a wire arc spray process using a novel feedstock formed as a hollow wire composed of aluminum or zinc, and filled with particles of oxides or carbides to produce a wear-resistant surface on a substrate.
In U.S. Pat. No. 6,683,271, to Rogers (which is hereby incorporated by reference in its entirety), one of the present inventors discloses a voltage-controlled wire arc spray wherein the wire feed motor of the two wires for the wire arc spray process receives power from the same power circuit that creates the arc spray operation such that the wire feed rate is automatically adjusted as voltage changes occur in the spray process.
This invention relates to wire arc spray systems and methods including, for example, wire arc spray systems for surfacing a substrate with non-slip properties, wherein the surfacing material adheres reliably to the substrate and is able to maintain its adherence at very high temperatures.
There is a need in the industry for a metallic or metalized, non-skid coating that provides heat resistance, wear resistance, slip resistance, corrosion protection to the substrate, long-term durability, a rough surface profile, and a high bond strength on all or many types of steels used in naval and other shipbuilding. A particular application for the present method is to provide a metalized surface on ship decks of all types, in particular, aircraft carrier decks for vertical lift aircraft that impart heat onto the deck surface.
Prior art technology does not exist for a sustainable, heat-resistant, non-skid coating system for vertical lift jet aircraft; and thermal spraying has not been used for this application. For example, the present method is suitable for use with a hollow aluminum and/or zinc wire filled at least in part with ceramic particles, such as the wire disclosed in U.S. Pat. No. 6,190,740 discussed above. This type of wire may sometimes be referred to herein as “Thermion® TH604 wire.”